1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to tune away in multi-SIM devices.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.
Additionally, some wireless devices are configured to facilitate communication on two separate networks via two separate subscriptions. For instance, dual-subscriber identity module (SIM), dual standby (DSDS) devices may include two SIM cards—one card for a first subscription and a second card for a second subscription. Furthermore, each subscription may be associated with one or more technology types. For example, a first subscription may exclusively support 2 G communication technology, such as Global System for Mobile Communications (GSM), while the second subscription may support one or more 3 G communication technologies (e.g. Wideband Code Division Multiple Access (WCDMA)) and 2 G communication technology.
In DSDS devices, a user may establish a call, such as a voice call, data call, data session, text messaging session, or any other data transfer session, via one of the two subscriptions. Because most DSDS devices contain a single radio resource, such as a transceiver, where a first subscription has established an ongoing call with a first subscription network, the UE must tune the transceiver away to the second subscription to receive necessary paging signals and to transmit, for example, message acknowledgement signals and/or measurement indication signals. Therefore, while the first subscription continues an ongoing call, the transceiver may periodically tune away from the first subscription to the second subscription to receive such necessary paging and/or control information.
Therefore, in DSDS devices, a user may engage in a data call via a first subscription, but must intermittently halt the data session to tune away to receive control data associated with the second subscription, which is typically in idle mode. This tune away may lead to reduction in data throughput on the first subscription for its ongoing data call, as no data transfer takes place relative to the data call while the device tunes away to the second subscription. What is more, the second subscription may hold the radio resources for a long period of time in order to complete software processing related to base station registration, which exacerbates the reduced data throughput problem on the first subscription. Tune away cannot be avoided completely, however, as the second subscription must periodically receive essential control data from its network, such as paging messages and the like.
Thus, methods and apparatuses are needed to allow for increased performance on the first technology as it continues an active data session while allowing the second subscription to tune away to receive essential messages.